dict0dict.h, dict0dict.c, row0mysql.c, ha_innobase.cc:

  Add some more safety if MySQL tries to drop a table on which there are open handles

innobase/dict/dict0dict.c

@@ -195,21 +195,6 @@ dict_mutex_exit_for_mysql(void)
 	mutex_exit(&(dict_sys->mutex));
 }
 	
-/************************************************************************
-Increments the count of open MySQL handles to a table. */
-
-void
-dict_table_increment_handle_count(
-/*==============================*/
-	dict_table_t*	table)	/* in: table */
-{
-	mutex_enter(&(dict_sys->mutex));
-
-	table->n_mysql_handles_opened++;
-	
-	mutex_exit(&(dict_sys->mutex));
-}
-
 /************************************************************************
 Decrements the count of open MySQL handles to a table. */
 
@@ -495,6 +480,41 @@ dict_table_get(
 	return(table);
 }
 
+/**************************************************************************
+Returns a table object and increments MySQL open handle count on the table.
+*/
+
+dict_table_t*
+dict_table_get_and_increment_handle_count(
+/*======================================*/
+				/* out: table, NULL if does not exist */
+	char*	table_name,	/* in: table name */
+	trx_t*	trx)		/* in: transaction handle or NULL */
+{
+	dict_table_t*	table;
+
+	UT_NOT_USED(trx);
+
+	mutex_enter(&(dict_sys->mutex));
+	
+	table = dict_table_get_low(table_name);
+
+	if (table != NULL) {
+
+	        table->n_mysql_handles_opened++;
+	}
+
+	mutex_exit(&(dict_sys->mutex));
+
+	if (table != NULL) {
+	        if (!table->stat_initialized) {
+			dict_update_statistics(table);
+		}
+	}
+	
+	return(table);
+}
+
 /**************************************************************************
 Adds a table object to the dictionary cache. */
 

innobase/include/dict0dict.h

@@ -26,13 +26,6 @@ Created 1/8/1996 Heikki Tuuri
 #include "ut0byte.h"
 #include "trx0types.h"
 
-/************************************************************************
-Increments the count of open MySQL handles to a table. */
-
-void
-dict_table_increment_handle_count(
-/*==============================*/
-	dict_table_t*	table);	/* in: table */
 /************************************************************************
 Decrements the count of open MySQL handles to a table. */
 
@@ -195,6 +188,16 @@ dict_table_get(
 	char*	table_name,	/* in: table name */
 	trx_t*	trx);		/* in: transaction handle */
 /**************************************************************************
+Returns a table object and increments MySQL open handle count on the table.
+*/
+
+dict_table_t*
+dict_table_get_and_increment_handle_count(
+/*======================================*/
+				/* out: table, NULL if does not exist */
+	char*	table_name,	/* in: table name */
+	trx_t*	trx);		/* in: transaction handle or NULL */
+/**************************************************************************
 Returns a table object, based on table id, and memoryfixes it. */
 
 dict_table_t*

innobase/row/row0mysql.c

@@ -273,8 +273,6 @@ row_create_prebuilt(
 	ulint		ref_len;
 	ulint		i;
 	
-	dict_table_increment_handle_count(table);
-
 	heap = mem_heap_create(128);
 
 	prebuilt = mem_heap_alloc(heap, sizeof(row_prebuilt_t));
@@ -1466,6 +1464,13 @@ row_drop_tables_for_mysql_in_background(void)
 	table = dict_table_get_low(drop->table_name);
 	mutex_exit(&(dict_sys->mutex));
 
+	if (table == NULL) {
+	        /* If for some reason the table has already been dropped
+		through some other mechanism, do not try to drop it */
+
+	        goto already_dropped;
+	}
+
 	if (table->n_mysql_handles_opened > 0) {
 
 		return(n_tables + n_tables_dropped);
@@ -1475,10 +1480,16 @@ row_drop_tables_for_mysql_in_background(void)
 							
 	row_drop_table_for_mysql_in_background(drop->table_name);
 
+already_dropped:
 	mutex_enter(&kernel_mutex);
 
 	UT_LIST_REMOVE(row_mysql_drop_list, row_mysql_drop_list, drop);
 
+        ut_print_timestamp(stderr);
+        fprintf(stderr,
+		"  InnoDB: Dropped table %s in background drop queue.\n",
+		drop->table_name);
+
 	mem_free(drop->table_name);
 
 	mem_free(drop);
@@ -1741,6 +1752,13 @@ row_drop_table_for_mysql(
 
 	if (table->n_mysql_handles_opened > 0) {
 		
+	        ut_print_timestamp(stderr);
+	        fprintf(stderr,
+		  "  InnoDB: Warning: MySQL is trying to drop table %s\n"
+		  "InnoDB: though there are still open handles to it.\n"
+		  "InnoDB: Adding the table to the background drop queue.\n",
+		  table->name);
+
 		row_add_table_to_background_drop_list(table);
 
 		err = DB_SUCCESS;

sql/ha_innobase.cc

@@ -981,7 +981,10 @@ ha_innobase::open(
 
 	/* Get pointer to a table object in InnoDB dictionary cache */
 
- 	if (NULL == (ib_table = dict_table_get(norm_name, NULL))) {
+	ib_table = dict_table_get_and_increment_handle_count(
+				      		     norm_name, NULL);
+
+ 	if (NULL == ib_table) {
 
 	  fprintf(stderr,
 "InnoDB: Error: cannot find table %s from the internal data dictionary\n"